1. Field of the Invention
The present invention relates to a motor-driven parking brake apparatus, and is applicable to, for example, a parking brake apparatus for a vehicle.
2. Description of the Related Art
Japanese Patent Application Laid-Open (kokai) No. 2006-17158 discloses a motor-driven parking brake apparatus which includes an electric motor; a shaft member which rotates about its axis upon receipt of rotational drive torque of the motor through one end of the shaft member; a conversion mechanism which converts rotational motion of the shaft member to translational motion of a translational movement portion; a cable having a first end connected to the translational movement portion; a parking brake connected to a second end of the cable; a load sensor for detecting axial load from the other end of the shaft member, the load being generated due to the tension of the cable; and a controller for controlling the electric motor on the basis of output of the load sensor.
In the motor-driven parking brake apparatus, since the load sensor detects the total axial load of the shaft member (hereinafter referred to as “total load”), the load sensor receives a large load. Therefore, the motor-driven parking brake apparatus has a problem in that the size of the load sensor must be increased in order to secure the strength of the load sensor.